Technical Field
Embodiments of the present invention generally relate to an image forming apparatus, such as a copier, a printer, a facsimile machine, or a multifunction peripheral (MFP) having at least two of copying, printing, facsimile transmission, plotting, and scanning capabilities, and an image forming system including a plurality of image forming apparatuses and a management device capable of communicating therewith.
Description of the Related Art
There are image forming apparatuses that form a background fog (i.e., background stain) pattern on a surface of a latent image bearer (e.g., a photoconductor), detect the amount of toner adhering to the background fog pattern, and adjusts a value of charging bias output from a charge power supply based on the detected amount of toner adhering, which is called “charging bias adjustment”.
For example, the following control operation is executed under a situation in which the accumulative running distance of the photoconductor from the previous charging bias adjustment operation is greater than or equal to a threshold, and the current environment (temperature, humidity, or both) is out of a preferable environment. While rotating the photoconductor, the charging bias supplied to a charging device to charge the photoconductor is changed stepwise. As sections of the photoconductor, charged under different charging bias conditions, sequentially pass a developing range opposing a developing device, a background fog pattern is formed on the surface of the photoconductor. Based on results of detection by a toner adhesion amount detector detecting the amount of toner adhering to each section (different in charging bias condition) of the background fog pattern, the relation between the charging bias value and the amount of background fog is identified. Based on the identified relation, the charging bias is adjusted not to cause background fog.